Article

Transcriptional profile of the intracellular pathogen Brucella melitensis following HeLa cells infection

Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, College Station, TX, United States.
Microbial Pathogenesis (Impact Factor: 2). 07/2011; 51(5):338-44. DOI: 10.1016/j.micpath.2011.07.006
Source: PubMed

ABSTRACT Brucella spp. infect hosts primarily by adhering and penetrating mucosal surfaces; however the initial molecular phenomena of this host:pathogen interaction remain poorly understood. Using cDNA microarray analysis, we characterized the transcriptional profile of the intracellular pathogen Brucella melitensis at 4 h (adaptational period) and 12 h (replicative phase) following HeLa cells infection. The intracellular pathogen transcriptome was determined using initially enriched and then amplified B. melitensis RNA from total RNA of B. melitensis-infected HeLa cells. Analysis of microarray results identified 161 and 115 pathogen genes differentially expressed at 4 and 12 h p.i., respectively. In concordance with phenotypic studies, most of the genes expressed were involved in pathogen growth and metabolism, and were down-regulated at the earliest time point (78%), but up-regulated at 12 h p.i. (75%). Further characterization of specific genes identified in this study will elucidate biological processes and pathways to help understand how both host and Brucella interact during the early infectious process to the eventual benefit of the pathogen and to the detriment of the naïve host.

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    [Show abstract] [Hide abstract]
    ABSTRACT: Brucella melitensis (B. melitensis) is gram negative, aerobic bacteria that cause Brucellosis in humans' sheep and goats. Brucellosis causes abortion in wild and domestic animals resulting in enormous financial losses. Therefore, the purpose of this study was to evaluate the clinico-pathological changes associated with Brucella melitensis infection and its bacterial Lipopolysaccharides (LPS) in male mice. Three groups of 24 Balb/c male mice consisting of 8 mice in each group were used as an animal model for the study. The control group were inoculated intraperitoneally with 1 mL of Phosphate Buffered Solution (PBS) pH 7 while, the treatment groups were inoculated intraperitoneally with 1 mL×10 9 of B. melitensis colony and 1 mL×10 9 of Lipopolysaccharides (LPS) extracted from B. melitensis respectively. Mice that showed severe clinical signs and those that survived were euthanized by cervical dislocation method after 5 days of post infection subsequently, post mortem was conducted and histopathological studies were carried out. B. melitensis group showed severe clinical signs between 6 to 17 h of post inoculation compared to the PBS and LPS groups. The LPS group became lethargic 2 h post inoculation but, they become active after 5 h post inoculation, while the control group (PBS) exhibited normal responses. Histopathology results showed severe tissue alterations in the reproductive organs of the B. melitensis group compared to LPS group. In conclusion, the atrophy of the spermatocytes in the testes and degenerative necrosis of the pseudo stratified epithelium of the vas deferens in the B. melitensis group were severe while, LPS group showed moderate atrophy of the spermatocyte of the testes and severe degenerative necrosis of the pseudo stratified epithelium of the vas deferens.
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